Hydrogen Purification through a Highly Stable Dual‐Phase Oxygen‐Permeable Membrane

Abstract

Using oxygen permeable membranes (OPMs) to upgrade low-purity hydrogen is a promising concept for high-purity H₂ production. At high temperatures, water dissociates into hydrogen and oxygen. The oxygen permeates through OPM and oxidizes hydrogen in a waste stream on the other side of the membrane. Pure hydrogen can be obtained on the water-splitting side after condensation. However, the existing Co- and Fe-based OPMs are chemically instable as a result of the over-reduction of Co and Fe ions under reducing atmospheres. Herein, a dual-phase membrane Ce_0.9 Pr_0.1 O_2-δ -Pr_0.1 Sr_0.9 Mg_0.1 Ti_0.9 O_3-δ (CPO-PSM-Ti) with excellent chemical stability and mixed oxygen ionic-electronic conductivity under reducing atmospheres was developed for H₂ purification. An acceptable H₂ production rate of 0.52 mL min^-1 cm^-2 is achieved at 940 °C. No obvious degradation during 180 h of operation indicates the robust stability of CPO-PSM-Ti membrane. The proven mixed conductivity and excellent stability of CPO-PSM-Ti give prospective advantages over existing OPMs for upgrading low-purity hydrogen.